text:
Why was the FDR of flight ET409 extracted from ocean transported dry instead of in water?
I was more than sure that FDR (as good as any other electronic device including magnetic strip, i.e. HDD), after sitting for a few days under the sea or ocean, must unconditionally be transported wet (i.e. inside some water container) to simply not let magnetic strips to get dry. The answers to this related question confirm this.
Yet, I have just saw a reconstruction and investigation of Ethiopian Airlines Flight 409 crash and noticed that:

FDR (found and extracted first) was transported dry, enclosed in an empty box,
CVR (found and extracted few days later) was transported in a box filled with water.

Is this just a "bug" in movie or can FDRs be transported dry after extracting them from sea / ocean?

I don't believe the issue is the tape "drying out". First it was dry to begin with, second most FDR's use solid state recording devices, not tapes anymore. The bigger issue is corrosion, they need to be carefully washed before they dry so the salt water doesn't destroy the internal parts.

@RonBeyer I'm asking about year 2010 crash. I don't believe that SSD-like solutions were used in FDRs, CVRs seven years ago, but I may be wrong.

@all I don't understand your decision. I'm asking, why in particular case FDR was not transported in water and you mark my question as duplicate pointing to an answer that says that is must be carried in the water. How original answer is supposed to answer my question?

Completely agree with the OP, this is asking about why in a specific case standard practice wasn't used.

@trejder: They were, in fact, already in use sixteen-and-a-half years ago.

@Sean What are we talking about here? You pointed out to a Wiki article's section which says that in AA77 crash a FDR with magnetic tape was used. Which supports my claim that SSDs were not used at that time. What was already in use 16,5+ years ago?

@trejder: Quoth the article in question - "On the other hand, all the data from the flight data recorder, which used a solid-state drive, was recovered."  My emphasis.

Update: solid-state FDRs have been around since at least 1992 (look under the "Flight Data Recorder" section), while solid-state CVRs have been around since at least 1993 (quoth the second-linked report: "It was the first solid-state CVR that the Safety Board has had the opportunity to read out for an investigation.")

As posted on Avherald, Lebanon's CAA released the final report in January 2012, detailing the investigation and its findings. The link on Avherald is broken, the current site for the CAA can be found here. The front page still links to a page on the report, where it can be downloaded.
Section 1.11 describes the recovery and contents of the flight recorders, and describes both recorders as being "immediately packed in water.".
See this fragment:

The DFDR was recovered from the Mediterranean Sea by the Lebanese Navy divers and turned over to the IIC in presence of members from the IC on 7 February, 2010. The DFDR was immediately packed in water to prevent/delay the onset of corrosion and transported to the BEA laboratory in Paris France under the custody of the IIC accompanied by a Lebanese and an Ethiopian IC members.

And this one:

A thorough hand search of the sea bed was then carried out the Lebanese Navy divers who finally succeeded in retrieving the CSMU and handing it over to the D/ICC in the presence of members from the IC on 16 February. The CSMU was immediately packed in water to prevent/delay the onset of corrosion and transported under the custody of the D/IIC and an Ethiopian member of the IC to the BEA laboratory in Paris France, for readout on 16 February, 2010.

While this could be inaccurate, it's much more likely that the reconstruction missed this point.


text:
Who assigns an arriving aircraft a runway and runway exit to use?
I recently bought a simulator for tower controllers (Tower! 2011) and have some questions about the responsibilities of the tower controller:

When an aircraft wants to land at 'my' airport I get contacted once they are established on the approach path and already have a runway assigned ("Tower, N1234 with you runway 26L").Unfortunately sometimes it happens that aircrafts are assigned a runway that is actually to short form them to land - which I found out the hard way by getting punished because the plane was not able to stop on the runway.Who is responsible to assign the correct runway in real-life, the tower controller or the approach controller? If if were up to the approach controller that would basically be a bug in the simulator.
Who decides which runway exit an aircraft will use after landing?Again in the simulator I can advise the aircraft to taxi to the terminal via a certain route ("N1234 taxi to terminal via L4 M4 N4") with L4 being the exit from the runway I want this aircraft to take. Unfortunately the aircrafts - in the simulator - decide which exit they are going to use on their own. So it might happen that the aircraft I assigned the route to exits the runway at exit L5 and therefore cannot comply with my assignment.How is that handled in real-life? Does the pilot land the plane and then report back where he is (if I queried the airplane for a position I get a "N1234 is on the ground") or does the tower controller assign an exit that the pilot needs to take - and therefore the simulator would have a bug?

The pilot can refuse a runway if he doesn't think he can land on it. If he does decide to land while he knows it is too short he is at fault.

The tower gives the ultimate clearance to land, though the approach controller (if one is available) assigns a specific approach to a runway in the approach clearance. I'm not sure about the game, however in real life if the runway was too short to land on, the pilot would report being "unable" to use that runway and would be assigned another runway instead. It is not the responsibility of ATC to ensure that the runway is long enough to land on.

Unless there is a NOTAM otherwise noting that a particular exit is unavailable for use, the pilot can slow down at whatever rate to vacate at any particular exit. However, once they've slowed down to taxi speed they should vacate as soon as practicable. The tower controller may request that a pilot vacates at a specific exit, but if they are unable to they will go for another exit.
After vacating the runway, the pilot notifies the tower that they are clear of the runway at a particular taxiway, and then will be (depending on the airport) be asked to switch to ground or be given taxi instructions.

Ok, sounds reasonable. Thanks for the answer - so it's basically how I thought and the game does not really reflect the real life.

notice that #2 is a direct result of Tenerife, where PanAm was assigned an exit and failed to use it, leaving the tower controlers and the KLM crew both in the fog and darkness to make the incorrect assumption that the runway was clear. Just one of the many communications failures that contributed to that accident.

When the tower can see the field, they don't normally ask you to report when clear of the runway because they can simply look out the window and see that you're clear. They normally only ask you to report it when visibility is low or obstructed from the tower.

I disagree with point #2.  AIM 4-3-20 says to exit at the first available taxiway or as instructed by ATC.  To me, that indicates that you are not to continue on the runway to C if you can safely turn at A, even if C would ultimately be more convenient.

@jwenting Where did you get that from? I can't find any evidence supporting that. It would be strange since the situation was that Pan Am was instructed to use the active runway as a taxiway. I such case (which is clearly different from a landing aircraft as described in the question) the controller could and still can instruct a specific exit which has to be used. Pan Am missed the exit but that was not really relevant to the communication breakdown. They never reported clear of the runway, instead they reported that they were still on the active runway (twice).

@DeltaLima there's an old book (maybe in Dutch only) about the accident and investigation. PanAm had instructions to use a specific exit, which they didn't take (probably because of the angle, the book says) and they didn't mention that to the tower. They didn't report clear of the runway, but they did report reaching that exit. The tower controllers were 1) inexperienced with heavies and dense traffic, 2 distracted, 3) operating in fog at night, 4) had a poor command of English.

@SteveV. First available is a bit ambiguous as it depends on how much braking is used. On one hand pilots are not expected to use first achievable (and heat their brakes to the maximum), on the other hand they cannot taxi past a couple of exits at 15 knots. By using tactical breaking crew have some wiggle room on their first available exit.

@jwenting Pan Am never reported reaching their exit. (See full transcript). Also the controllers were not operating at night, it was 17:02, sunset was 19:21. What changed as a direct result of the accident was the use of the word take-off which is now used exclusively in the take-off clearance. (KLM took off without take-off clearance).

@Qantas94Heavy - DeltaLima's point about skipping exits at 15kt was what I was getting at.

@SteveV.: well that wasn't my intention to imply that, I'll fix up the post.

The approach controller is responsible for assigning the runway to the aircraft, but the pilot of the aircraft is responsible for verifying the runway is long enough for his aircraft and rejecting the approach clearance if he feels it is unsafe. The tower will ultimately give the landing clearance as they have the detailed picture of what is going on at the runway. Note that it is a landing clearance, not an instruction.
The tower controller can request a runway exit to be used for landing aircraft, however ultimately the pilot is free to choose. If he cannot make an exit or it would require excessive braking a pilot will elect to take a later exit. In general pilots will vacate as soon as practicable not to cause interference with other traffic.
Once the aircraft has vacated the runway, the pilot will be given taxi clearances either from the tower controller or from a ground controller on a separate frequency.

The Tower controls the runways and therefore designates active runways for arriving and departing traffic.  Typically this is done based on current surface winds and aircraft type.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Is there a downside to trying multiple flight instructors?
My local airport has a Part 61 flight school and gives students the option of selecting among three Certified Flight Instructors. Farhan and others have posted excellent explanations of characteristics to look for in instructors.
Other than wasted time and money, is there any downside to doing an "Introduction to Flying" lesson with each of the three instructors and seeing which one I like best? Similarly, am I likely to offend CFI's that I'm "looking around" other options?

No. Definitely try more than one CFI and ideally, more than one school. This is the smart choice and one I recommended regularly when I was an active flight school CFI.
You're about to spend a ton of money - do the due diligence and spend more up front to make sure you don't waste time and money with someone whose teaching style or personality clashes with you as a student.

The only thing I would add is once you find an instructor you mesh with it's advantageous to stick with them (at least for the most part - sometimes you might want a fresh perspective).

@voretaq7, I totally agree.

My first flight instructor was kind of a jerk.  You know the kind: First flight, "Let's take the plane for a SPIN", "How about a BREAKFAST ROLL?"  After a few hours into my training, there was a scheduling conflict and I got a different instructor - a military pilot with many thousands of hours of flying time and a very different attitude. Professional. He worked me harder than the other instructor ever had.
The flight school eventually canned my first instructor.  He moved across the field and took on new students at a different school.  Then there was the day one of his students almost ran over me in the pattern.  They were flying a Cessna and I was flying a Grumman.  The tower had cleared them AFTER me, but they apparently never even saw me and pulled into the pattern on the downwind right underneath me.  Fortunately, both I and the tower realized what was happening, so I just maintained altitude and extended the downwind leg and the tower cleared the Cessna ahead of me.
When I called up the flight instructor to tell him about the near mishap, his attitude was quite cavalier.  He seemed to think it was funny.
Shop around.  If you can find a military instructor with thousands of hours of flight time, odds are you'll find a very serious teacher.

As mentioned it's a good idea. You will be spending a lot of time with this person in a very confined space, not only should you trust their abilities but should at least get along with them. FWIW I would not consider this a waste of time as the hours will count towards your total and you will be learning new things while trying new instructors.

I think many instructors is a good idea, since you see their different
characteristics and each has their own sweet spot. I had at least
10 different instructors for my PPL, and learned a lot from the differences as
well as their similarities.

There is no harm trying out different instructors. Note that instructors have different strengths. Some may be better at teaching tailwheel and others at instruments.
One problem is that you will not really be able to tell the difference between a good instructor and a better one in one flight, unless it is a personality issue. From a technical point of view it will be hard to tell.
Better instructors tend to get booked up and are hard to schedule. If your instructor's schedule looks really full, that is a good sign he is a good one. Also, look at their flying experience. I notice that the better instructors tend to have more flight hours.
Once you start flying be sure to get "check rides" from other instructors once in a while. Different instructors have completely different styles and areas of emphasis, so it can be very useful to get "alternative points of view" from time to time. A new instructor will usually teach you new stuff. In this sense, even a bad instructor can be good sometimes because they can teach things maybe your usual instructor does not know.
Beware of "easy" instructors that just soft shoe everything. They are the nicest instructors, but they are slow teachers and they can be derelict and just "go with the flow" when they should be correcting you. If one or two instructors tell you that you should not fly and are not cut out to be a pilot, the dumbest thing you can do is to find an easy instructor who will just collect your money, even though he knows you are not pilot material.

I disagree that flight experience logged reflects upon the quality of instruction one is likely to receive. I know several experienced older instructors who do a terrible job at preparing students for life as a pilot. I've also flown with incredible instructors who had yet to graduate college. Experience is great, but no replacement for natural teaching ability, or for a good education.

@egid Its an average measure not an absolute. I have just noticed a correlation trend between hours and CFI skill. Obviously there are plenty of exceptions.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Did Pacific Southwest Airlines ever operate flights under VFR?
Does anyone know if Pacific Southwest Airlines (PSA) ever flew certain routes under VFR?
I've read this question and I understand that Part 121 does allow for VFR flight, but my question is specific to PSA. I've heard they routinely flew low altitude VFR flights on shorter routes throughout California.

I was a controller at L.A. Center around that time, and it was extremely common for airlines on the short-haul routes to go VFR-on-top, which is VFR but on an IFR flight plan. There would have been a lot of downsides to flying VFR but every advantage to them to fly VFR on top: with on-top they didn't need clearance into class B (back then the TCA) or get refused or delayed because the controller was "too busy"; didn't have to fly airport patterns (basically guaranteed a straight-in since they would be on an instrument approach); and for flying into the metered airports like LAX or SFO they would have a guaranteed slot, unlike trying to call up as a VFR where they would go to the back of the line and might have to hold for an hour. Plus of course on-top has the benefits of not needing IFR separation, so ATC would almost always give them a direct routing and they could climb all the way up to 16500/17500 instead of being step-climbed under everyone else and capped at maybe 10,000.
So while I don't remember specific routine flights from 25+ years ago, I do remember working a LOT of airlines flying VFR on top on the short routes like LAX to Bakersfield, Burbank to Fresno, etc.

Nice perspective. Thanks & welcome to Aviation.se!

Well, there is nothing to indicate in 14 CFR 121 or 135 that an aircraft cannot operate under VFR for a revenue flight.
For very short hops at low altitudes in good weather, a VFR flight can make a lot of sense since it is simpler to conduct, adds less congestion to ATC and may allow the flight to reach its destination more quickly.
For most revenue flights for regional, transcontinental or intercontinental destinations, an IFR flight is preferred, or even mandatory, due to uniformity in ATC routing, operations at high altitudes - Class A or equivalent airspace - and greater operational flexibility in marginal weather.

Yeah, in the U.S., you have to stay below FL180 in order to operate VFR, which, on airliners, is horribly inefficient for all but the very shortest flights.

PSA operated propeller-driven aircraft in its fleet for some time before switching to jets.

It's important to understand the difference between visual procedures, visual flight rules, and visual meterological conditions.
Airliners always operate under instrument rules because it guarantees them ATC services, and because it's a requirement for proceeding into instrument meterological conditions (IMC).  Also, higher airliner flight level altitudes are reserved for planes on instrument flight plans.
In instrument meterological conditions, only instrument procedures are used.  But in visual meterological conditions (VMC), airplanes operating under instrument flight rules (i.e., those following instrument flight plans) are often required to perform visual procedures like flying visual approaches, or maintaining visual separation from other airplanes.

"Airliners always operate under instrument rules". This is true more often than not, but it is certainly not always the case.

Since PSA flew from 1949 to 1988, I'd imagine that a lot of current regulations didn't apply to them, especially in their early years.

FWIW, both 747 carriers I worked for in the 1990s had provisions in their ops specs for VFR operations.


text:
What are the dimensions of the protected space provided by a holding pattern?
What are the dimensions of the protected space provided by a holding pattern? Where and how does the FAA define this?
While this question may contain the answer, this question concisely asked something that is a valid aviation question and it warrants its own answer.

This information is available on the answer here. This is defined in Order 7130.3A.

While wbeard52's answer on the other question might answer this one as well, this question itself is entirely different and deserves an answer itself.

Albeit the body of the question is different, this question has an answer in the linked one and as per SE practice this is to be considered duplicate.

If someone searches for the size of the protected hold area which question are they going to find first? It deserves a concise answer.

"closed" does not mean "bad". it can be closed and stay without answers, the link will redirect the searcher to the answer.

@Federico I think that redirecting to the other question in this case isn't helpful. The questions are completely different, so what happens if someone edits that reply to remove the information that answers this question? That's very possible: the protected area is irrelevant to identifying wind correction, so someone may update it to remove that information. I personally think the reply to the other question isn't very good (see my comment on it) for exactly that reason.

The exact answer to your question is found in a 500 page document titled "United States Standard for Terminal Instrument Procedures (TERPS)" that was revised and issued as Order 8260.3C on 03/14/2016. This is the answer to the part of your question about "where does the FAA define this."
As mentioned, the FAA uses templates. There used to be 31 templates of various sizes that are identified by pattern numbers 1 through 31. However, Patterns 1-3 are no longer in use. So there are now only 28 in use. Originally, these templates were literally plastic transparent templates. Now, most holding patterns are constructed using automation (i.e. computers). The following figure shows the exact proportions and geometry of every one of the 28 holding patterns in use today.

Point "L" (little orange circle) is the holding fix. This is a standard right hand holding pattern, (left hand holding patterns were drawn by flipping the plastic pattern over for a symmetrical left-handed pattern). The solid black line that runs from point "M" to point "L" is the holding course. All the straight line segments are defined by the definition of the respective Pattern Number as provided in the following chart.

Take a look at the dimensions of Pattern Number 4 on the chart above. Pattern 4 is the smallest holding pattern in use today. Specifically, see that the column M-E says 5.3 nautical Miles, and that column L-I/M-H reads 3.5 nautical Miles. Now look at the template in the figure above and find the line M-E. This is the protected distance from the holding course on the Holding Side of the pattern. Now, find the lines L-I and M-H. These represent the protected distance from the holding course on the Non-Holding side of the pattern. This is the answer to the part of your question about "what are the dimensions of the holding patterns and how does the FAA define it."
RANT:
Now my rant. I often hear pilots and even flight instructors talk about the "Protected Side" and the "Non-Protected Side" of the holding pattern. This is inaccurate. The FAA does not describe holding patterns in that way. There is either a Holding Side or a Non-Holding Side. BOTH sides are protected! Pattern #4, the smallest pattern in use in the USA, has 3.5 nautical miles of protection on the Non-Holding side. I plugged in all of the values in the chart above into Excel and calculated the ratio of Non-Holding Side protected area to Holding Side protected area, and all of the patterns had a protected area on the Non-Holding Side equal to approximately 2/3 or 67% of the Holding Side. That may not be as much protection as on the holding side, but it translates into multiple miles of protection.
Next time someone says Non-Protected Side of a holding pattern, take the time to explain to them that both sides are protected. Protection on the Non-Holding Side is necessary to protect aircraft entering a holding pattern using a parallel entry with a cross-wind that is pushing them away from the inbound course into the Non-Holding side during that initial 1 minute outbound entry.
End of RANT

There's no single, simple answer to this. As the FAA's Holding Pattern Criteria order explains, they actually have 31 pre-defined sets of dimensions for different altitudes:

2-9.  SIZE AND NUMBERING.   There are 31 holding airspace sizes.  Each is related to one or more even-numbered altitudes/flight levels
  and is identified by a template number for easy reference.
2-10.  TEMPLATES-SCALING AND TRACING.   Templates numbered to correspond with pattern numbers were developed in sectional chart
  scale (1:500,000) and should be used to determine protected holding
  airspace.

It seems that a lot of variables were taken into account, as mentioned in this FAA commentary:

31 holding pattern templates  were developed to fit over 100 different
  combinations of indicated airspeed (IAS), altitude,  and distance from
  facility in the case of ground-based navaids.  Averaged seasonal winds
  aloft were part of this extensive 1964 evaluation

Chapter 2, Section 1 of the Order gives more details on those factors. The order also has instructions for making a template manually and it lists all the dimensions needed to define the protected airspace (see page 2-16, table 3). It's too much information to show here (and SE markup doesn't support tables) but there is a very wide range of values, e.g.:

Template 1 has a total length of 11.6 nm and width of 6.7 nm
Template 4 has 14.4 nm and 8.8 nm (as shown in this answer to another question)
Template 16 has 34.7 nm and 21.0 nm
Template 31 has 84.9 nm and 57 nm

The largest holding patterns are suitable for use where holding at higher then normal speeds is required; up to 280 kts.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
How does the V-22 Osprey share engine power between its rotors?
I learned through a comment on this question about multiple engines powering a single propeller that the V-22 Osprey can power both rotors from a single engine, or use both engines to power a single rotor. What are the mechanical systems that make this possible?

It is possible to drive the two rotors of the V-22 Osprey from a single engine using a segmented driveshaft connecting both engine shafts via gearboxes:

The drive shaft is depicted in blue in the left wing. Source
Each engine drives its own rotor and the connecting shaft. If one fails the same rotation speed is maintained, but each rotor receives now half the power of the remaining engine.
A similar mechanism is also used on the CH-47 Chinook family:

Source
This is a CH-47 Chinook green drive shaft:

Source
On aircraft with two distant rotors, it is vital to have both rotating, as if one slows or stops the aircraft is unbalanced to the extend it crashes.

What happens if an engine fails/seizes in a way that the connecting shaft becomes immovable? Does that cause both rotors to fail, or is there a mechanical linkage that can disconnect from the failed engine?

@hexafraction It wouldn't matter, either one is an unflyable aircraft. The V-22 cannot fly on a single prop/rotor and neither can the CH-46/47.

@hexafraction , if the engine fails, normally the shaft is not affected. If, for some reason, the shaft rotation is in prejudice, both rotors will lose RPMs in synchronization (this will eventually cause lift loss and a crash because, even with autorotation, the breaking force can exceed the upwind traction of the maneuver).

If, in other scenario, the shaft breaks apart at some point, rotors will be out of synchronization. In synchropters and tandem ones, they will probably collide with each other; in tilt rotors they don't touch their selves, BUT even if they are free from the shaft motion, THEORY says an autorotation can be attempted, but strong and progressive roll oscilations will happen as rotors differences of RPMs causes the aircraft to swing side do side (the upwind flow raising when one wing falls, causing the rotor to recover lift and switch the other side to do the same, like a seesaw). In this case...

...the aircraft is strongly in danger to the proportion of the height, because this side to side rolls will become more and more violent until the aircraft rolls over the point of autorotation efficiency (rotors being feed by sides rather from beneath) and a last roll will cause it to, eventually, invert and crash. Smaller heights can (again, in theory) increase the survivability because the aircraft will have no time to develop violent oscilations, reaching ground at a possible lower vertical speed. All of this is valid for speeds under ~60 knots, where wings are not providing enough lift.

Just to inform, I'm the same @Germano Cavalcanti of the answer ahead, just had some troubles with that account. ;)

Tilt rotors and virtually every other VTOL aircraft with more than one lift rotor (Chinook, K-Max) or proprotor (AW609) must employ a shaft between these lift units, so when one engine is out the other keeps the units turning with half power (which doesn't mean half rotations per minute, but half maximum torque). That's why available power reserve on the engines of these aircraft is important; choosing engines that are 'just enough' for the normal job may deny their certification for obvious safety reasons. A failure or a simply deceleration of one rotor/proprotor would cause disastrous asymmetry of lift along the aircraft center of mass.
Also, many of these aircraft require the rotors to be permanently synchronized (and, therefore, connected) simply to avoid collision between their counter rotating blades. In tilt rotors, rotor sync is also beneficial when talking about vibrations, acoustics and symmetry of aerodynamic flow through the airframe. Finally, connected proprotors are also a solution towards simplicity regarding yaw: the AW609, for example, doesn't have a rudder, since it can yaw by simply changing the blade pitch of one proprotor (or changing both in opposite angle values).
That's why every aircraft with connected rotors/props and two or more power plants slowly spins all the blades even when only one engine is starting. Since the first transmission of output inside the engine is done through air without a mechanical shaft connection (using the free turbine solution), the engine doesn't suffer that much from overload. Over pressure in the combustion chamber may be an issue, but is easily addressed with bleeding valves and/or FADEC protections.
The details of those connection shafts are not very new, resembling the shafts that connect the main and tail rotors on heavy helicopters of traditional design, but far more robust and having no reduction gears. They are basically assembled with the least amount of segments possible. The connections between them must be as precise as possible, withstanding some difference of torque between the segments in order to avoid over twist efforts that could lead to failure. Also, they can't absorb differences of angular momentum (like the springs on a manual car transmission clutch do) since this can easily evolve to a resonance between the rotors.

The cross shaft of the V-22 is normally unloaded.  It only takes up the load if an engine fails, at which point everything continues as normal albeit with reduced power.  Alternatively, if the shaft is damaged, but you've still got two good engines, the aircraft flies as normal because the shaft isn't being used anyway.  On the CH-47, though, the shaft is always under load because that's how the front rotor is powered by the engines in the rear.  If that shaft is damaged, it will result in an immediate loss of the aircraft, even with two good engines.

For the CH-47, why couldn't a driveshaft breakage be dealt with by completely shutting down both engines and autorotating down?


text:
What examples of Janitrol heater failures can be found in NTSB reports?
What examples of failures in Janitrol heaters can be found in NTSB reports?
As a bit of background, the gasoline heater is a small, gasoline-fueled heating device commonly found in light twin aircraft such as the Cessna 414.
What I'd like to do is compile a list of the associated NTSB reports for all known failures of Janitrol heaters that caused an incident. I'd also like to note which cases had a favorable result and what actions the pilots took to handle the situation.
The answer may eventually lead to a discussion of depressurizing the cabin of pressurized aircraft to put out a fire. While this approach won't work with some fires, it might apply to this situation. This question about in flight fire is relevant to that discussion.

I found 17 hits in the NTSB database for "Janitrol" but I don't feel like reading through them all to see if the units really contributed to an accident or not ;-)

You have to wonder why anyone would post a query asking a question about a search you can easily do yourself....


text:
Aircraft pitch and AOA change during a coordinated turn maneuver
Let us say I am flying a constant airspeed turn while maintaining my altitude, when I enter into the turn, lift has to be increased and since airspeed remains constant, the AOA has to be increased to increase lift; so I pulled up the column and increased the elevator deflections to nose up the aircraft to maintain altitude. How is the pitch attitude changed during this maneuver? Does the pitch angle remain the same as the pitch before entering the turn? Is the equation Pitch = AOA + FPA (FPA is zeroed in this case, I think) still applicable during this turn maneuver?

Peripherally related -- https://aviation.stackexchange.com/a/16538/34686

Interestingly enough, if the plane "purely" rolls around its longitudinal axis, it will be in a slip condition for the turn. (From the earth reference) the coordinating rudder pushes the nose "down".  So, the nose will be higher in a slip.  Sort of answers why R/C planes can do aileron only turns.  They are light and (generally) overpowered.

Just in case previous comment 2 days ago wasn't clear, I'm basically offering an "unofficial bounty" w/ no expiration date, that I'll fulfil by setting up a real bounty when the appropriate time comes, to anyone who offers some reasonably careful, relevant, and detailed actual in-flight observations pertaining to this question, based either on visual observations of pitch attitude, or on observations of attitude indicator etc, or both.  Happy flying!

In anticipation of soon deleting many of the comments above, I created a chat room to talk about ways to carry out actual in-flight experiments addressed toward this question. The chat room is called "Practical techniques for observing small changes in aircraft pitch attitude" and the link is https://chat.stackexchange.com/rooms/136402/practical-techniques-for-observing-small-changes-in-aircraft-pitch-attitude.  Thanks, and happy flying.

You can see I've added an answer, but I still intend to reward, as described above, any other answer that includes careful in-flight observations, ideally using an actual attitude indicator, set carefully to be zeroed when the aircraft is actually level.  It would then be good to do the test at as low an airspeed as is safely possible, and a higher airspeed, and see if results differ.  45 degrees bank would be a good choice for the turning portion.  Would then be good to then repeat the experiment with the reference dot on the attitude indicator intentionally set way too low, and too high.

And if the geometry of the aircraft permits it-- basically need a headrest to help hold head steady, and/or a "mast" out in front of windscreen that projects above horizon for a gunsight-- make a mark on windscreen/canopy right on horizon in level flight, and see whether rises/ falls as enters a turn.  Extra points for doing the test an aerobatic aircraft w/ a symmetrical airfoil and zero wing incidence, for reasons described in my answer-- but most don't have attitude indicators I suspect.

Specifically, pitch relative to the horizon = arcsin(sin($\alpha_T$)$\cdot$cos($\phi$)) where $\alpha_T$ is the pitch relative to the flight path and $\phi$ is the angle of bank.  Pitch relative to the flight path is an inextricable linear function of n.  And n = sec($\phi$).

Does the pitch angle remain the same as the pitch before entering the
turn? Is the equation Pitch = AOA + FPA (FPA is zeroed in this case, I
think) still applicable during this turn maneuver?

No, that equation is not applicable during banked flight.  Consider the following thought experiment: assume zero wing incidence.  Assume we are flying horizontally with wings level (no bank) at 10 degrees angle-of-attack.  The pitch attitude will be 10 degrees.  Now we roll (around the aircraft's longitudinal axis) instantly to a bank angle of 90 degrees. We've converted 100% of our angle-of-attack into sideslip, which we might also call "yaw angle".1   But the pitch attitude, as shown on the attitude indicator (see this related answer for depiction of attitude indicator) is still the same. Now, we might note that the aircraft will almost certainly not be in equilibrium in this new attitude unless pilot makes major changes to control inputs (applies top rudder, relaxes all elevator back pressure) and power setting, and possibly also allows the airspeed to change. But the key point that's  relevant to the current question is that once the aircraft is banked 90 degrees,  anything that the pilot does with the elevator at this point to change the aircraft's angle-of-attack will have zero immediate2 effect on the pitch attitude, shown on the attitude indicator.  Likewise, if the aircraft were banked 45 degrees, a given change in angle-of-attack would have less effect on the aircraft's pitch attitude, as shown on the attitude indicator, than if the aircraft were wings-level.
So no, the formula "pitch angle = flight path angle + angle-of-attack" does not apply to banked flight.  The correct formula is:
pitch angle = flight path angle + (angle-of-attack * cosine bank angle)
It follows therefore that if the flight path remains horizontal (i.e. if altitude remains constant), any given increase in pitch angle represents a greater increase in angle-of-attack if the aircraft is banked than if the aircraft is wings-level. And the difference is given by the cosine of the bank angle.
So what happens to the aircraft's pitch attitude as the aircraft enters a banked turn, while holding altitude and airspeed constant?  Let's start by simplifying the problem by assuming that the wing has no twist (washout), has a fully symmetrical airfoil, and is mounted to the fuselage at zero degrees incidence.  Since the required lift force (for horizontal flight) is equal to the weight / cosine bank angle, it logically follows that as the pilot increases the bank angle, while also increasing the angle-of-attack as needed to hold airspeed constant, and also increasing power as needed to hold altitude constant, the aircraft's pitch attitude should remain constant, if the slope of the curve of lift coefficient versus angle-of-attack is linear.3,4
Why might this seem counterintuitive?  I'd suggest that one reason is that in actual practice, pilots rarely attempt to hold airspeed constant while entering a turn.  If cruising at a high airspeed, well on the "right side" of the power-required curve, many light airplanes will be unable to maintain altitude in a steep turn unless the pilot increases the angle-of-attack enough to actually cause some decrease in airspeed, despite the increased wing loading.  For shallower turns, if short in duration, many pilots may just leave the throttle alone and accept a decrease in airspeed as they apply back pressure as needed to maintain altitude while entering the turn, even if more power would actually be available if the throttle position were changed.
But read on for other reasons why a pilot typically will observe an increase in pitch attitude as he or she enters a turn while maintaining constant altitude and airspeed.
Consider the effect of adjustments to the height of the "index" dot on the attitude indicator.  If the pilot has, for convenience, set the attitude indicator to show a pitch angle of zero in unbanked horizontal flight, even though the aircraft is actually slightly nose-up to create the required angle-of-attack, will it still be true that no change in indicated pitch attitude will be seen if the pilot enters a banked turn while holding airspeed and altitude constant, given the assumptions noted above of a lift curve with a linear slope, etc?  One way to think about this is to imagine an attitude indicator with two reference "dots" rather than one, one vertically (in the aircraft's reference frame) below the other.  It's clear that as the aircraft rolls from wings-level into a steep bank, only one of these "dots" can remain on a constant pitch attitude reference line on the attitude indicator.  If the upper "dot" remains on a constant pitch attitude reference line, the lower dot will end up on a higher pitch attitude reference line than it started at, indicating that the aircraft's pitch attitude has increased.  Similarly, if the pilot has selected a visual reference point on the cowling that is below the "ideal" or "correct" reference point, then as the aircraft enters a banked turn while holding altitude and airspeed constant, that visual reference point will appear to be rise, in terms of its apparent distance above or below the horizon -- and here we're using "up" and "down" relative to the reference frame of the earth, i.e. perpendicular to the line of the horizon.
So if the "height" of the reference dot on the attitude indicator (or the "height" of the visual reference point on the aircraft's cowling, windscreen, etc) makes a difference, what is the "correct" way to set the height of the reference dot on the attitude indicator, or to choose a visual reference point?  If the observed pitch attitude is to remain the same regardless of bank angle, assuming a linear slope to the curve of lift coefficient versus angle-of-attack, it appears that the pitch attitude must be measured in relation to a line that is parallel to the zero-lift line of the wing5.  If the wing has positive incidence relative to the fuselage, or if the wing has a non-symmetrical airfoil so that it still produces some lift at zero degrees angle-of-attack, then the appropriate reference line will be inclined in the nose up, tail-down direction in relation to the actual longitudinal axis of the fuselage.  In this case, setting the reference "dot" on the attitude indicator to be right on the horizon in actual wings-level cruising flight will cause the indicated pitch attitude to increase as the aircraft enters a banked turn while maintaining altitude and airspeed.  And similarly, a visual reference point that was right on the visual horizon6 in actual wings-level cruising flight would rise above the horizon as the aircraft enters a banked turn while maintaining altitude and airspeed.7  But a visual reference point on the canopy chosen such that a line from the pilot's eyes to that point was parallel to the zero-lift line of the wing should stay a fixed distance above or below the visual horizon-- measuring perpendicular to the horizon, rather than in the aircraft's own local plane of "up" and "down"-- as we enter a banked turn while holding altitude and airspeed constant.
In summary, here are some reasons why we typically observe an increase in pitch attitude as we enter a banked turn, while holding altitude and airspeed constant, even given the assumption of a wing with a linear curve of lift coefficient versus angle-of-attack:

If we are making observations simply by picking a point on the cowling or nose that lies directly ahead of the pilot (in the left-right sense) in wings-level flight, a line from the pilot's eyes to that point will always be inclined significantly downwards in relation to the longitudinal axis of the fuselage, which means that that point would always tend to rise toward the horizon (measuring perpendicular to the horizon, not in the aircraft's own local up-and-down plane) if the aircraft were to increase bank angle while maintaining a constant pitch attitude relative to the horizon.  This would give the false impression of a nose-up change in pitch attitude.

Due to wing incidence and due to having a non-symmetrical (cambered) airfoil, the zero-lift line of the airfoil is not aligned with the actual longitudinal axis of the aircraft.  This causes an actual nose-up change  in (fuselage) pitch attitude as the aircraft enters a banked turn while holding altitude and airspeed constant, even in the ideal case where the slope of lift coefficient versus angle-of-attack is linear.

Even in aircraft with a fully symmetrical airfoil, mounted to the fuselage at zero incidence, if we "zero" out the reference dot on the attitude indicator in wings-level flight, or if we pick a visual reference point on the windscreen that is right on the horizon in wings-level flight, we're still using a reference line that is not parallel to the zero-lift line of the wing (and the longitudinal axis of the fuselage.)  This will cause an increase in the indicated or apparent pitch attitude, even if the actual pitch attitude remains exactly constant as the aircraft enters a banked turn while holding altitude and airspeed constant.  To see an indication of a constant pitch attitude as we increase the bank angle, we'd have to set the reference dot on the attitude indicator to correspond to the aircraft's actual pitch attitude in wings-level flight, or pick a visual reference point on the windscreen, etc that was an appropriate distance above the horizon to correspond to the aircraft's actual pitch attitude in wings-level flight.

Disclaimer-- the geometry involved here is complex.  My intuitive hunch would have been that the aircraft's pitch attitude would need to increase as bank angle is increased in a constant-altitude constant-airspeed turn, even in the idealized case of a fully symmetrical wing mounted to the fuselage with zero incidence.  I haven't confirmed any of the results given in this answer by reference to any outside sources, nor have I actually made any in-flight observations to confirm or contradict these results.
It would be most interesting to see answers to this question based on careful observations in actual flight (particularly, recent observations made with a fresh and open mind, for the specific purpose of answering this question.)  Links to video including a clear view of the attitude indicator would provide added value.  The most interesting results might be obtained from an aircraft with a fully symmetrical airfoil, mounted to the fuselage at zero degrees of incidence.  Answers based on observations from high-quality flight simulators might also be of some interest.
Footnotes:

Using "yaw angle" to describe the angle, in the yaw plane of rotation, between the aircraft's longitudinal axis and the actual direction of the flight path, would be an informal or non-standard usage.  In this answer to a related question, in the discussion of "Euler angles", the concept of "yaw angle" would clearly correspond to the aircraft's heading, not the sideslip angle.  The basic point remains that rolling toward a steeper bank angle tends to convert angle-of-attack into sideslip.  However, unless the roll rate is very high and the aircraft's intrinsic pitch stability and directional/yaw/"weathervane" stability are quite low, this dynamic will tend to be obscured by the aircraft's tendency to return to the "trimmed" angle-of-attack and slip angle, i.e. the angle-of-attack and slip angle corresponding to the current position of the flight controls.  So this "conversion" of angle-of-attack into sideslip is surely not the primary reason that we need to apply rudder along with ailerons to keep the ball centered while rolling in most aircraft.  Normally, aerodynamic yaw torque due to displaced control surfaces, and also due to the "twisted" nature of the relative wind while rolling and the resulting "twist" in the lift and drag vectors, are the key drivers of slip while rolling.  "Your mileage may vary", particularly if you are flying an aircraft with minimal aerodynamic adverse yaw, relaxed directional/weathervane/yaw stability, and a lightning-fast roll rate.

Re "zero immediate effect" -- we're referring to the immediate relationship between a rotation about the aircraft's pitch axis, and the aircraft's pitch attitude.  At 90 degrees bank, they are completely de-coupled.  Of course, in the longer term, changing the angle-of-attack will change the drag coefficient, which will influence the airspeed, which will influence the amount of skyward aerodynamic force produced as the aircraft flies along in a slipping attitude (knife-edge flight), which will affect the trajectory of the flight path, which will affect the aircraft's pitch attitude.

Re "if the slope of the curve of lift coefficient versus angle-of-attack is linear in that part of the flight envelope"-- this is indeed a good approximation for much of the flight envelope for most aircraft, especially with unswept wings.  See for example this section of the excellent "See How It Flies" website by John S. Denker.  See also this image.  (Source of image is unknown, but similar content appears in the book "Aerodynamics for Naval Aviators".

This observation is inspired by similar content in this related answer to the same question-- yet the alert reader will notice some significant differences in the explanation as to "why" this is so, including the mathematical formulae.

Re "If the observed pitch attitude is to remain the same regardless of bank angle, assuming a linear slope to the curve of lift coefficient versus angle-of-attack, it appears that the pitch attitude must be measured in relation to a line that is parallel to the zero-lift line of the wing."-- the point is that if the curve of lift coefficient versus angle-of-attack is linear but the y-intercept is not at 0 degrees angle-of-attack, we essentially must shift our angle-of-attack measurement so that it's zeroed when the wing is creating zero lift.  For a given airspeed, lift will be directly proportional to this "shifted" angle-of-attack, not the actual angle-of-attack, and for a given bank angle and airspeed, lift will be directly proportional to (1 / (cosine bank) multiplied by this "shifted" angle-of-attack, not the actual angle-of-attack.  Similarly, a "shifted" pitch attitude that is measured relative to the wing's zero-lift line, not the aircraft's actual pitch attitude measured relative to the longitudinal axis of the fuselage, is what we should expect to remain constant as we vary the bank angle while holding airspeed and altitude constant.  If the pitch attitude measured relative to one particular reference line (e.g. the zero-lift line of wing) remains constant as we vary the bank angle (under any given set of constraints, such as while holding altitude and airspeed constant), then the pitch attitude measured relative to any other reference line (e.g. the longitudinal axis of fuselage) cannot also remain constant.  See footnote 7 for more.

Here we're assuming that the visual horizon line is not depressed below the true horizonal plane due to the earth's curvature.  If the visual horizon line is significantly depressed below the true "horizontal" plane, this will cause a shift in the aircraft's perceived pitch attitude, but this shift appears to be independent of bank angle, bearing in mind that pitch attitude is measured perpendicular to the horizon, not in the aircraft's own local plane of "up" and "down".  So any depression of the visual horizon line due to the earth's curvature ought not complicate the relationship between changes in bank angle, and changes in resulting (apparent) pitch attitude, while airspeed and altitude are held constant.

One way to think about this is to recognize that if the wing has positive incidence, then for horizontal flight at any given angle-of-attack, the aircraft's nose is depressed earthwards less when the aircraft is banked than when the aircraft is wings-level, again measuring perpendicular to the  horizon, not in the aircraft's local up-down plane.  The same logic applies to a sightline defined by the line between the pilot's eyes and a spot on the cowling out in front of the pilot-- this line always slopes downward (earthward) in wings-level flight, and the earthward slope of this line always becomes less when  aircraft is banked, so the selected spot on the cowling will always move up toward the horizon as the aircraft is banked while holding the pitch attitude (as defined either by the longitudinal axis of the fuselage or the zero-lift line of the wing) constant.

Some other related content on ASE:
A: What is the relation between roll angle and pitch angle?
Q: How does the angle of attack vary in turns? -- (see various answers)

@RobertDiGiovanni -- re "One important change would be to omit or modify "pilots rarely hold airspeed constant when entering a turn". This is in fact a great way to keep them safe. 90 knots is prerequisite for a 60 degreee steep turn in a 172."-- I see your point, will think about it.  Depends to some degree on how steep a bank angle we are talking about it.  For more moderate turns of short duration, leaving the throttle alone avoids need to mess with again later after turn is finished--

An analogous concept is the yaw string ahead of CG showing deflection even though plane is coordinated.  What helped me was to aim my wrist to a point in space with the index finger as the nose with AoA.  Then rotate the wrist to 30, 45, 60, 90 degrees.  In your writings about curved coordinated flight you have spoken much similar concepts.  I'm believing a bit more, especially regarding very long winged sailplanes.

So, rather than the usual "Dueling Banjos" approach to our answers, (even better with John and Michael) please allow me to propose that  rolling into a turn cannot be a "pure" roll about the longitudinal axis, it is actually a roll, pitch, yaw corresponding to aileron, elevator, and rudder.  As seen from the line of flight, the plane rolls and pitches.  How great it would be for us to describe it mathematically!

Let us continue this discussion in chat.

(Some content has been added to chat)

pitch angle = flight path angle + (angle-of-attack * cosine bank angle)
is still an approximation, but a pretty good one.  A more complete formula comes from setting vertical speeds equal and is sin(pitch)*cos(AOA) = sin(FPA) + sin(AOA)*cos(bank)*cos(pitch), and even that doesn't include wind.

@CodyP -- thanks for the comment-- wind is surely irrelevant though.  Circling a/c doesn't tend to pitch up or down every time it passes through dead-upwind or dead-downwind headings.  I need some time to absorb the rest of your comment.  Is the "pitch angle = flight path angle + (angle-of-attack * cosine bank angle" equation 100% true in cases where the flight path is horizontal?  If not, can you help me understand why not?

(Ctd)  Or does the relevant constraint need to be in cases where the pitch angle is zero?  (which would imply a/c is descending at a descent angle exactly equal to angle-of-attack?  One thing's for sure, the three dimensional geometry is complex.

(Ctd)  I do have some actual in-flight observations to report but it will take a little time to sort them out well enough to submit as an answer and I'm not sure that they are completely consistent.    I'm leaning toward the conclusion that there is very little change in pitch attitude in either direction as bank angle is increased from say 0 degrees to 55 degrees while holding airspeed and altitude constant, but don't quote me on that, might say something different after finished reviewing notes.

@CodyP -- interested in your feedback, but maybe best to continue in the chat room?  (See link above.)  Either way fine by me but mods may delete long strings of comments.

Excessive editing, which you have been asked to refrain from previously. Locking.

Pitch attitude will be increased slightly as one rolls into a bank to increase the AoA in order to maintain a vertical component of lift equal to the weight of the aircraft.  In addition power or thrust will be increased slightly when entering the turn to compensate for an increase in induced drag, as a consequence of increased AoA, and maintain a constant airspeed.  Rudder will be used, as required, to counteract adverse yaw, both during the roll into the bank and once the turn is established.
For very shallow banked turns an increase and pitch will only be slight, if anything at all.  For moderate or steeply banks turns, the increase and pitch will be much more noticeable, as the required lift in the turn increases.

Let us say I am flying a constant airspeed turn while maintaining my
altitude, when I enter into the turn, lift has to be increased and
since airspeed remains constant, the AOA has to be increased to
increase lift; so I pulled up the column and increased the elevator
deflections to nose up the aircraft to maintain altitude. How is the
pitch attitude changed during this maneuver? Does the pitch angle
remain the same as the pitch before entering the turn?

Observations from actual in-flight experiments--
Aircraft: Glassflugel Libelle sailplane
The aircraft had no attitude indicator (artifical horizon), but the pitch attitude was observed in two different ways, described below.
Results: When the aircraft transitioned from wings-level flight at 50 mph to a stabilized 45-degree banked turn at the same airspeed, the pitch attitude shifted slightly in the nose-up direction.
Conclusion: If the same aircraft had been flying under power at the same airspeed, with the power varied as needed to keep the vertical speed at zero so that the altitude remained constant, the variation in pitch attitude would have been in the same direction as described above, but slightly larger in magnitude.  So in this case as well, the pitch attitude would have been more nose-high in a constant-banked turn than in wings-level flight at the same airspeed.
Methods of observing pitch attitude:

While pilot's head was held firmly in position against the top of the canopy (using a folded cloth as a cushion), a mark was made on the front of the canopy to represent the position of the horizon in wings-level flight.  Then it was carefully noted whether the mark ended up above or below the horizon when the glider was established in a turn.1,2

An array of bubble levels (to cover a wider range of angles than could be measured with a single bubble level) was attached to each side of the cockpit wall.  Each bubble level was oriented in the fore-and-aft direction, i.e. as viewed from above, parallel to the aircraft's longitudinal axis.  The bubbles were observed to note whether they were displaced forward (indicating a pitch change in the nose-up direction) or aft (indicating a pitch change in the nose-down direction) in circling flight, compared to in wings-level flight.3

Footnotes:

The observed change in pitch attitude was small enough that it was only consistently detectable when the great care was taken to keep the pilot's head exactly fixed in position.  The relatively close proximity of the front of the canopy to the pilot's eyes in this particular aircraft added to the challenge of getting reliable measurements.  This method would be easier to use if the windscreen or canopy were further from the pilot's eyes.  If the windscreen or canopy is out of the pilot's reach, a series of closely spaced reference marks, oriented vertically, should be applied before flight.

Note that there's a presumption that this sight line is nearly parallel to the longitudinal axis of the aircraft.  Looking over the geometry of this aircraft, this appears to be a reasonable presumption.  The related answer Aircraft pitch and AOA change during a coordinated turn maneuver goes into more detail in the geometry involved here, but in short, in any given transition between wings-level flight and a steady-state turn, regardless of what parameters we specify are being held constant (e.g. airspeed, angle-of-attack, pitch attitude), there is always some fore-and-aft reference line on the aircraft that stays in a constant "pitch attitude" relative to the horizon.  (If this reference line happens to coincide with the aircraft's longitudinal axis, then we say that the pitch attitude is remaining constant.)  In the same transition between wings-level flight and turning flight, any reference line oriented more tail-up/nose-down than the line described above will experience a nose-up shift in pitch attitude, and any reference line oriented more tail-down/nose-up than the line described above will experience a nose-down shift in pitch attitude.  This is a simple function of geometry, not aerodynamics.  Another way to explain this is to note that, while transitioning to wings-level flight to turning flight, if the reference "dot" on an attitude indicator is seen to stay at a fixed pitch indication, then adjusting the height of the dot upwards would cause the indicated pitch attitude to shift in the nose-down direction during the same transition, and adjusting the height of the dot downwards would cause the indicated pitch attitude to shift in the nose-up direction during the same transition.  So if an aircraft were flying in an extreme nose high pitch attitude, then a reference line drawn from the pilot's eyes to the horizon would be aimed well below the actual longitudinal axis of the aircraft, and would tend to give an overestimate of any increase in aircraft pitch attitude during the transition from wings-level flight to turning flight, and might actually give an appearance that the pitch attitude was increasing, when it was in fact staying constant or decreasing.  Note also that by the same logic, since in most aircraft (including the glider described here) the zero lift line of the wing is inclined significantly upwards (nose-up, tail-down) in relation to the aircraft's longitudinal axis in horizontal flight (or in a sailplane that is gliding efficiently), the observed increase in pitch attitude described here is actually not inconsistent with the idea that the zero-lift line of the wing is keeping a constant angle with the horizon, as viewed from the side.  This would be consistent with the idea expressed in other answers that as the bank angle is increased, the increase in angle-of-attack might be exactly geometrically compensated for by the increase in bank angle, so that the actual pitch angle of some given reference line does not actually end up increasing.  This statement was clearly not true in these experiments if we pick the aircraft's longitudinal axis for the reference line, but it might be true of the wing's zero-lift line.  It would be most interesting to repeat these experiments in an aerobatic aircraft with a symmetrical airfoil and zero wing incidence.  It seems possible that in such a case, the aircraft's pitch attitude might be the same in a constant-altitude banked turn, as in wings-level flight at the same airspeed.

Note that in a steady-state turn (constant airspeed, vertical speed, bank angle, and pitch attitude), as viewed from the side, the bubble in a level mounted in this fashion will seek to position itself in curved tube of the level so that it is oriented "straight up" relative to the earth.  As long as the level is not mounted so that it is "toed in" or "toed out" relative to the aircraft's longitudinal axis as viewed from above, it will not be affected by the forces that displace the slip-skid ball during a slip or a skid.  A slip-skid ball instrument, mounted parallel to the aircraft's longitudinal axis as viewed from the side, rather than in the usual orientation on the instrument panel, could also have been used for this experiment.  Naturally, it would tend to orient itself "straight" down relative to the earth, not "straight up".  And it goes without saying that none of these instruments will orient themselves "straight up" or "straight down" relative to the earth, if the flight path is curving earthward or skyward-- e.g. during a loop-- that's why we can't use bubbles or balls to fly in clouds.

For extensive comments / discussion, consider using this existing chat room -- https://chat.stackexchange.com/rooms/136402/practical-techniques-for-observing-small-changes-in-aircraft-pitch-attitude .  Thanks.

Experiments were actually conducted in 2 different gliders, but to avoid multiple edits, I'll wait till I'm ready to add the details in full.

Airspeed in test in Libelle was 50 mph.  Actually several other speeds were tested, still need to go through notes and see if result was consistent in every case.

My current thinking is that observations made with bubble levels, and observations made by "gunsighting" the horizon by making a mark on the canopy, ought to always agree (at least if the "dip" of the horizon is negligible, which it appears to be.)  They are measuring the change in "pitch attitude" of an imaginary line drawn on the side of the fuselage parallel to the horizon,  just before the maneuver (change in bank angle etc) is carried out.

For the reasons explored in my other, more theoretically-based answer, and in the chat room linked above, this is not necessarily the same as the change in the aircraft's actual pitch attitude, i.e. the change in the angle of the aircraft's longitudinal axis in relation to the horizon.

For this reason I think using these methods on a glider will give poor results at very high airspeeds, and/or with the spoilers open, because in these cases the aircraft's longitudinal axis is inclined significantly downwards in relation to the horizon.   I don't see that as being a problem in tests carried out at lower airspeeds, such as 50 mph, where the glide angle is very flat.  Still interested in seeing tests carried out in a powered aircraft, with constant altitude, using an attitude indicator, and ideally also using some of these other methods as well, as a cross-check.

Discuss further here - -https://chat.stackexchange.com/rooms/136402/practical-techniques-for-observing-small-changes-in-aircraft-pitch-attitude

Pic source
Aircraft pitch motion is defined relative to the aircraft: when it rolls, the pitch axis rolls with it. And seen from the plane, pitch angle is still Angle of Attack plus Flight Path Angle - zero deg. in a coordinated turn at constant altitude.
From this site
On the instrument, indicated pitch is relative to the banked horizontal, all quantity reference lines bank with it. The horizon on the instrument is a memory of earth gravitational field, and is therefore relative to earth axes. Indicated pitch angle on the instrument is relative to where the horizon was in horizontal flight = pure pitch.

@quietflyer The sentence was open to improvement indeed, thanks.

@quietflyer when rolling, the pitch axis roll with the plane, and the crux of the matter is that pitch angle is defined relative to this rolled pitch axis. Pitch is defined in the aeroplane axes coordinates. But indeed, FPA is defined in earth axis, I'll update the answer.

"Aircraft pitch motion is defined relative to the aircraft" ? Really? Perhaps I don't understand what you mean by by Pitch Motion. So you would say that Pitch angle is still positive when in a 20 degree dive ? If defined by the Aircraft that would be the implied conclusion. I'm not arguing, just wondering what you are actually saying. Clarity is crucial.

@CharlesBretana Well that is a good question: how is zero pitch angle defined, at which angle of which axes orientation? The usual convention is with the pitch and roll axes level with the horizon.

that is exactly how I would define it, it is relative to the horizon, not to the aircraft. Yes, pitch angle is the position of the nose, or the fuselage reference line, relative to the plane of the horizon.

@CharlesBretana When in level flight, absolutely. However, from for instance the wiki for Aircraft Principal Axes: "These axes move with the vehicle and rotate relative to the Earth along with the craft. These definitions were analogously applied to spacecraft when the first manned spacecraft were designed in the late 1950s."

Not sure what your point is there...  My initial reaction is - Exactly! the axis  are fixed to the vehicle, and move with it, they are not relative to the vehicle, they rotate relative to the earth, not to the vehicle.   Are we agreeing? or disagreeing ? My only (trivial) comment originally was that where you said that "Aircraft pitch motion is defined relative to the aircraft". It is not, it is defined by the position of the aircraft (fuselage reference line), relative to the earth.

Let's say you are in level constant speed linear flight where AoA = Pitch to the horizon.
Roll to 45 degrees and vertical lift is now cosine bank angle × lift = .707 × Lift.  Pitch (to the horizon) is now also .707 of (level flight) AoA, or 70.7%, because the aircraft has rolled 45 degrees from horizontal into a new plane of flight.  As a result, it's AoA points into the circle, as does the lift vector.
Lift is approximately linear to AoA so:
AoA must be increased by around 41% to keep flight path in a circle level to the horizon.
1.41 × .707 = 1!  Your pitch to the horizon is the same in the turn as in level flight because the plane is banked, but AoA is higher.
It is easy to confuse "pitch to the horizon" and "pitching the aircraft". Validation of the term "pitch angle" as the longitudinal axis of the aircraft relative to the horizon can be found here.

I'm not at all sure you are incorrect, but the lift curve (Lift Coefficient vs Airspeed) is not always linear The slope of the CL curve for swept wing aircraft continuously decreases... That might imply that the pitch attitude (vs. the horizon)might not obey the same trig relationship as that which governs the total lift to weight relationship in a bank. See https://i.sstatic.net/WYfpz.png

Well, I'm going to stick to 172s for now.  But we seem to agree pitch will be AoA related, so why not use the curve for a specific plane to determine pitch at what angle.  What you are saying is for (your) swept wing aircraft, pitch will be greater in a turn (unless you correct the deficiency by dropping a little slat and flap).

Robert, yes, that's exactly what I am suggesting!

@RobertDiGiovanni, thanks Robert and I could understand the AOA needs to be increased 41%  more than AOA in level flight, but how did you get to the conclusion that "1.41 × .707 = 1! Your pitch to the horizon is the same in the turn because the plane is banked, but AoA is higher."

Picture the plane rolled 90 degrees.  It's pitch (to the horizon) is zero.  For a given AoA "1" = 100%,  roll 45 degrees.  Pitch is 70.7% or .707, but now you must increase AoA by 41%.  So your 45/45/90 lift triangle is no longer .707/.707/1, it is 1/1/1.41.  In the vertical, pitch now has 100% of its original value.  As Charles Bretana pointed out, this holds true where the lift/AoA relationship is linear.

@RobertDiGiovanni, sorry but still confused that how you get the correlation that pitch = AOA*cos(Bank Angle)

@VvW OK, increase AoA first by 41%  Now, how far do I have to roll to keep from climbing?  Remember, a 90 degree roll has no pitch.

@RobertDiGiovanni, so in 0 bank level flight, AOA = Pitch and in 90 bank level flight, Pitch = 0, thru that we could conclude pitch = AOA*cos(Bank Angle)?

@VvV yes, that would be turning AoA (sufficient to maintain vertical lift)*cos(Bank Angle).

Interestingly, from referenced diagrams, it rotates around its CG, which rests at the line of flight.  So, if a pitched aircraft (relative to the horizon as AoA) rolls, the nose scribes a circle, hence the trigonometry of its angle to the horizon?

Interesting flight behavior is what is called Inertial Coupling. Early in F-16 life cycle, we lost a few Vipers due to this Phenomena.  Fighter pilots are taught to acknowledge that they have been shot by a rapid wing rock. When performed aggressively, at high AOA, the F-16 could roll so fast that the rotational inertia of the mass of the ends of the aircraft (Nose and tail), moving in a circle around the flight path, would, by centrifugal force, cause the AOA to increase out of  bounds and cause aircraft loss of control. So just rolling with aileron does NOT cause a slip.

@CharlesBretana one may take caution in extrapolating your (great story nonetheless) to a lowly very stable 172.  The point here that is being forged (with much sweat and hammering) is that aileron only (and adverse yaw) puts the nose outside the turn (actually) outside and high due to the bank. This is a slipping turn.   An F-16 is very unstable in comparison.

@Robert, Yes, in 172, this happens because of the [uncorrected] adverse yaw, which throws the nose opposite the direction of roll, to the outside of the turn. In the F-16 (or any fly-by-wire or yaw damper equipped) aircraft , those systems prevent the uncoordinated reaction to the adverse yaw, and the nose would not skew to the outside.  As you correctly point out,  I guess my previous comment should have used the phrase Coordinated Roll, instead of rolling with aileron.

If you want to maintain 2Gs, your bank angle must be 60 degrees.
And your a/c will be needed more lift to maintain altitude. So the only way to produce more lift without changing config’ is pulling up your stick to make your nose up. This pulling up motion will increase the gap between flight path and nose(AOA). So for maintaining 60 bank angle and altitude, your nose have to be upped more than level.

But curious question remains... what will the pitch attitude, (as defined by vertical angle between the fuselage reference line, FRL), and the horizon), be? Yes, the angle between the FRL and the flight path must increase, but it does this in a plane that is tilted relative to the horizon at the angle of bank. Indeed, my initial guess would be that the same trigonometric relationship that governs the lift required to hold level flight at any specific bank angle would also apply to the increase in pitch attitude.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Is preplanning approach management best practice and why didn't pilots seem to do it 50 years ago?
There are lots of recreation of flights where the pilots seem to look at the approach chart and all approach considerations just before they begin their approach for the destination airport. This seems to just asking to make serious mistakes. Is it current best practice to consider the destination airport approach (and somewhat alternates) before departing? And why wasn't done a long time ago?

Your question is a little muddled. (E.g. currently consider the considerations?) Yes, it’s always a good idea to be familiar with approaches before departing. The level of effort spent during preflight planning depends on weather, experience and familiarity. I'm curious, what is the basis for this observation of yours?

An airport near me has a staggering 53 approaches.  Which one(s) do you suggest pilots review beforehand?

The one you must likely to assigned and general details of all approaches.

I eventually downvoted your question because you are assuming that pilots 50 years ago didn't consider IAPs during preflight planning without providing a basis for your claim, and you ignored my question about it.  Were you in a position 50 years ago to regularly observe instrument rated recreational pilots during preflight planning?

The assumption embedded in your question is simply wrong.

What assumption? PIA Flight 268 https://www.youtube.com/watch?v=ypRFJdlnwzk

You're making the claim "why didn't pilots seem to do it 50 years ago?" based on one accident?

It is always a good idea to be familiar with the approaches into your destination airport before you depart. But it's also a good idea to review the approach just before starting it, especially after what might have been a long flight.
This is further complicated by the fact that you don't necessarily know which approach you will be assigned until you get there. Sure, you can include a specific approach in your flight plan, but that's no guarantee. If the weather changes, or the airport ATC reorganizes the flow of traffic, or if the controller just feels like it, they may assign you a different approach from what you looked at before you took off.

Briefing an approach is always a good idea.  As a CFII, I teach my students to review and thoroughly brief an approach on the ground prior to the flight in order to carefully review the IAP in order to catch unique features and difficulties associated with the approach. Some approaches a pretty straightforward, others can have nuances that are difficult to spot a casual glass or notes that need to be followed.
In flight, I teach people to fly approaches by BRAVE’M
Brief - review the approach and all information in preparation to fly it well in advance of when you were going to receive a clearance to do so.
Radios - set your COMMS to the appropriate frequencies and have needed freqs ready in the stnby slots as well
ATIS - copy down your ATIS report at your destination airport ASAP.
VORs, GPS & & Other NAVAIDS - set your NAV radios, GNSS, etc as required to fly the approach.  Load your approach, and your GPS and make ready to activate it per ATC instructions. Set up a make ready to use the autopilot for the approach and missed procedure, if you have it available.  This includes planning for and setting up your navigation equipment to fly the missed approach, if required to do so.
Establish and Execute with ATC clearance - establish and/or fly the approach per ATC clearance. Activate APR mode on the autopilot, if available.
Missed - be prepared to fly the published missed approach procedure, or following ATC instructions as required if, for any reason you either cannot continue to execute the approach or descend below minimums.
By default, your briefing of the approach in the air cannot be as detailed as a code on the ground, given the demands of PIC.  This is why it pays dividends to brief approaches prior to flying the airplane.  That being said, I also understand that going into high density, traffic, environments, and other demands from ATC, you may not get the exact approach that you wanted. You have to be able to quickly adapt to ATC instructions as well.


text:
What velocity is used to calculate maximum range and maximum endurance?
These are my data;

$C_{L_0} = 0.4$
$C_{L_{\alpha}} = 5.7$
$C_{L_{minD}} = 0.14$
$C_{D_{min}} = 0.022$
$k = 0.035$
$\alpha_{stall} = 15$
$S_{ref} = 20m^2$

Mass Data

$W_{total} = 2500 \text{ kg}$
$W_{fuel} = 800 \text{ L}$
$\rho_{fuel} = 800  \text{ kg/m}^3$
$mass_{fuel} = (1/1000) \cdot W_{fuel} \cdot \rho_{fuel} \text{ kg}$   , 1/1000 l from coverting into m^3
$g = 9.807   \text{m/s}^2$  gravity

Propulsion Data

Engine_type = "Internal Combustion Engine"
Propeller_type = "Constant Speed Propeller"
S_prop = 1.9 # m^2
n_prop = 0.8 # %80
SFC_takeoff = 0.28 # kg/kW/h
P_takeoff = 400 # HP
P_maxCont = 350 # HP
SFC_maxCont = 0.25 # kg / kW /h
P_cruise = 280 # HP
SFC_cruise = 0.2 # kg/kw/h

My main purpose is calculate maximum range and endurance at constant velocity and altitude. So that I have started to calculate $C_{L} = C_{L_0} + alpha * C_{L_\alpha}$  to find $V_{stall}$ and $C_{L_{max}}$. Well I have different $P_{cruise}$ and $P_{takeoff}$. I am uncertain how to proceed because I didn't decide, or am uncertain how to decide, which one of speeds I need to use TAS, or $V_{cruise}$. I decided to calculate CD by using the Quadratic Drag Model because this model's result is more accurate than a simpler one according to what I have read. $CD = CD_{min} + k * C_{L}^2$
That is my duty;
Start the calculation with the aircraft at an
altitude of 20,000 ft. and a full tank of fuel and finish the calculation when there are 100 litres of fuel
remaining. For both the (a) range and (b) endurance analysis, provide separate results in cases when (i) the
velocity [TAS] is kept constant and (ii) the altitude is kept constant. In all cases, the angle of attack
should be kept constant. During this analysis, you can use the cruise SFC value.
And well, I couldn't start the step-by-step calculations in a regular sequence. I am hoping that someone can or will help me to determine proper sequence.

def calculator_atmosphere_values(h):
    # S-L reference values

    rho0 = 0.002378  # slugs/ft^3
    P0 = 2116  # psf
    T0 = 518.67  # R

    #############################
    Temperature_Ratio = (1 - 0.0000068756 * h)  # k values lapse  rate constant = 0.0000068756 / ft
    Pressure_Ratio = (1 - 0.0000068756 * h) ** 5.2561
    Densitiy_Ratio = (1 - 0.0000068756 * h) ** 4.2561

    #############################

    T_uk = Temperature_Ratio * T0 # R
    P_uk = Pressure_Ratio * P0 # psf
    rho_uk = Densitiy_Ratio * rho0 # slughs/ft^3

    ####################################################

    rho = rho_uk * 515.378818 # converting to kg/m3
    T = T_uk / 1.8 # converting to Kelvin
    P = P_uk * 47.88 # converting to Pascal

    ####################################################

    print("################### Temperature  according to Height ######################")
    print(f"Temperature at {h} Altitude: {T} K")
    print("################### Atmospheric Pressure for Altitudes below 36.089 ft ######################")
    print(f"Pressure at {h} Altitude: {P} Pa")
    print("################### Atmospheric density according to Height ")
    print(f"Density at {h} Altitude : {rho} kg/m3")

    return T, P, rho, T_uk
```

"my problem is determine Vcruise" what do you mean? $V_{cruise}$ is the speed at which you want to cruise, it's a given parameter not one that you calculate. Maybe you want to calculate maximum speed? Or speed for best endurance? Or speed for best loiter? Or stall speed?...

Hi Bugra, welcome to aviation.stackexchange.com. I started to convert your parameters to MathJax for better readability. Please check if I made any mistakes and correct them if needed.

Can you show what you have done so far? What are you trying to achieve at cruise speed? Maximum range or maximum endurance?

yes exactly what i want calculate Max range and Max endurance  constant altitude and speed ,
I have done calculate pressure, temperature and density at 20.000 ft by using     Temperature_Ratio = (1 - 0.0000068756 * h)  # k values lapse  rate constant = 0.0000068756 / ft
Pressure_Ratio = (1 - 0.0000068756 * h) ** 5.2561
Densitiy_Ratio = (1 - 0.0000068756 * h) ** 4.2561
these equation. I also calculated CL = CL0 + alpha * CLa i have alpha at stall so that I calculated CLmax and Vstall and after i calculated Thrust value T = (P * (746 / 1000) / 0.2) * np # Newton at Cruise

@Bugra you would be better to edit the detail into your question. If you have a look at the syntax for mathjax, it will make it much more readable.

@Jamiec okay I appologise for that I didn't know how can i use that syntax. Is it okay now

Then what you're looking for is the "Breguet range equation" and the "loiter endurance equation"

Great, I'm glad I could help  Maybe you can post an answer yourself when you're finished

This is sort of a "do my homework" request, but it may be helpful to realize holding a constant angle of attack will mean a faster airspeed with a full tank and a slower airspeed with 100 liters remaining.
You may then use your drag coefficient and airspeed data to calculate thrust requirement, then determine fuel consumption rate to provide that thrust from the time the fuel tank is full to the time it contains 100 liters.
The lift requirement decreases by the weight of the fuel burned.

Indeed, this is a prompt to set up a variety of integrals and see how their results differ. The 'constant alpha' and simple drag polar will mean that flight occurs at constant CL, which means constant CD and constant L/D. Since W will vary, D will vary, but in simple terms, the integral can be written in terms of weight. Then things start to go off the rails...
They're told to work the problem in two forms - one constant TAS, the other constant altitude. In both cases, power required will change - and are unlikely to ever equal the specified cruise power. But, eta and SFC are constant.

@RobMcDonald this is where common sense takes over.  Gliders commonly vary their Vbg based on weight.  Optimal wing AoA is critical.   I'd look into the Breguet equation.

well, I selected  CLminD so that I got CD = CDmin after than I calculated Vcruise speed by using T = D equation then calculated TAS, CAS, EAS and then I am goin to using TAS to finding R according to the Breguet equation constant velocity and altitude conditions. Am i going right?

@Bugra yes.  I would do min fuel consumption first, then go have a talk with whoever gave the assignment.

@bugra You can't set CD=CDmin.  Although the name makes you think that is possible, that would be a condition for zero lift -- perhaps flying a parabolic arc, but that is not a condition for T=D and L=W.

CDmin for level flight is at Vbg.  Would this not be min fuel consumption per mile for a jet.

Thanks for all, well I started to calculate CD by Adjusted Drag Model in Gudmundsson. This CLminD  is it  good selection for  calculating Max Range and Endurance ? and also we could assume some variables is that free whatever it assumed


text:
Were European single-engine fighters considered superior to U.S. designs at the start of WW2?
There was a wide consensus in U.S. military circles about 1940 that U.S. pursuit fighters were substantially less capable in terms of performance than their equivalent European counterparts. Specifically, in Germany, the BF109-E (the first version to use the Daimler-Benz DB-601 engine) began production in 1938, while the original airframe was designed in 1934. In Britain, the Spitfire airframe was designed in 1935 and the airplane went into development and testing up to, and after, the start of production in 1938 or 1939. The single-engined fighters which were being developed in the U.S. at the same time were the Seversky P-35, Bell P-39, and Curtiss P-40. There was wide belief - confirmable by various performance metrics, that the U.S. fighters were inferior.
What accounted for this difference in performance? Let's assume for the moment that the discipline regarding aircraft structures was largely settled and was evolving incrementally in practice.  Consequently, advances in aircraft performance would have been governed by developments in 1) aerodynamics and 2) propulsion.  How did developments in these two areas progress during the war, and how did that influence aircraft production?
Keeping this in mind, one reason, for example, that immediately jumps out is that the European engines at this time were of higher performance in terms of power than similar engines then available in the U.S. The German DB-601 and British Rolls Royce Merlin engines were both superior to the American Allison engine, the only serious V12 the U.S. produced in the late 1930s. It would take until 1940 for the U.S. radial engine makers to launch high-output versions of their radial engines (e.g., super-turbocharged R-2800s) and of course the U.S. capitalized on the high-performance, liquid-cooled Merlin for use in the P-51, rather than undertake more immediate development and improvement of a similar engine by Allison.
So the question is, was the entire scope of the performance difference due to powerplants alone, or, as the war progressed, were there other salient developments in aircraft propulsion and aerodynamics that improved the performance of American fighter aircraft relative to comparable British and German fighters?

Some say the U.S. was very isolationist after WWI and didn’t see a need to produce state of the art aircraft.

Paragraph 3: "Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much." You're asking for an entire history book here...

You are a mod, so obviously I defer to you. But I'm not sure how I can scope this more appropriately. I am curious about why U.S. fighters had poorer performance in the 1935-40 era, and particularly curious about non-powerplant developments that contributed to the performance delta. It's a broad topic, but wasn't sure where else I could ask the question.

the US was very isolationist, not interested in the military
as a result the US defense budget was very very low, there was next to no money available
in part as a result of that purchase programs were extremely conservative, no "experiments" were allowed

All that led to the US purchasing biplanes and open cockpit monoplanes like the P-26 and F2F at a time the Germans were fielding early Me.109s and the UK Hurricanes.
It also led to other areas of the US military being very outdated and understrength. The US armour units were still using FT17 tanks and close derivatives from WW1 for example, the US Navy's ships overall were barely evolved from their WW1 counterparts (though there there was an initial problem in that the US clung to the Washington Naval Treaty limitation way past when other nations had abandoned that treaty, a treaty that also limited the size of US carriers and thus limited the performance of their carrier aircraft).


text:
Where does Air Force One refuel?
Obama came to Greece and then to Germany. That's a long trip, even for the majestic Jumbo. There was a lot of discussion about where the aircraft was refuelled during that trip. Do we know, in general, where Air Force One is refueled?
There were claims that it was refuelled in the air by American aircraft, but isn't that more costly than refuelling on the ground?

Relevant: after Germany, they headed to Lima, Peru, a distance too far to fly without refueling. As such, they landed at Lajes Air Base, Azores for a brief stop to refuel, then proceeded to Lima.

@ZachLipton a "a United States Air Force detachment unit", as Wiki mentions.

To add a last note to the answers: Mid air refuelling is dangerous. You don't want to to it with a president onboard unless you have a VERY good reason to do so.

Note: technically speaking, "Air Force One" is the callsign of any Air Force aircraft while the president is on-board, and only while the president is on board. The two VC-25As are equipped for mid-air refueling, and I am guessing, they sometimes do refuel in mid-air, but according to the quote in @ymb1's answer, they never refuel in mid-air with the president on board, which means never when they are actually acting as "Air Force One".

Presumably they could fly both jets (which gives some ambiguity as to which one he's actually on), refuel the one he's not on, and then move him to the jet that's full when it's on the ground. Though that seems a little convoluted for typical circumstances!

I think they should re-fuel the one that he's not on, and then transfer him to the other one in mid-air.  http://www.historyinsidepictures.com/siteimages/AIR%20B11.JPG

I can't confirm whether either VC-25 has refueled in flight while acting as AF1 but the aircraft is so equipped for the job.
I do know refueling on the ground depends on where the jet is and the quantity and quality of fuel available onsite.  The USAF insists on using fuel that it supplies for security reasons.  For operations in Western Europe the fuel  is trucked in from nearby military bases.  When the jet visits more remote nations such as in Africa or Asia, fuel is flown out to the jet in fuel trucks loaded aboard C-17s.  Strangely enough, this is really how it works!

I was stationed at Hickam AFB, Hawaii, during a Presidential trip to Asia, and detailed to assist during the layover to refuel both VC-25s.  (Yep, always bring a spare jumbo jet when flying overseas ;)  The fuel for the planes was loaded onto refueling trucks in advance, and after it was tested the trucks were kept under special guard on the flightline to ensure it wasn't tampered with.

The VC-25A (which is usually used as Air Force One) can definitely make the trip from Washington D.C. to Athens in one fuel tank! I think the longest the VC-25A has gone without refuelling is from Washington D.C. straight to Riyadh, Saudi Arabia (although this is only done in advantageous wind conditions. 70% of the time, the plane stops in Ramstein Air Base or RAF Mildenhall to refuel before continuing on to Riyadh.)
Usually, if Air Force One decides to refuel, it does so 90% of the time at one of the five following bases:

Joint Base Elmendorf-Richardson (Alaska)
Ramstein Air Base (Germany)
RAF Mildenhall (United Kingdom)
Hickam AFB (Hawaii)
Yokota Air Base (Japan)

These five air bases are located so strategically throughout the world that the VC-25A rarely needs to stop elsewhere for fuel. There are, of course, exceptions, such as when President Trump flew to Vietnam in 2019, he took off from Washington, refuelled at RAF Mildenhall (one of the five bases mentioned above) and then refuelled another time at Al-Udeid Air Base in Qatar before finally making it to Hanoi. And YUP you read that right, he really did stop two times just to refuel, which is rare but not unprecedented. President Obama also stopped two times when he went to Vietnam back in 2016: first at Joint Base Elmendorf-Richardson and then another stop at Yokota Air Base (both bases were mentioned above) before finally reaching Hanoi.
Hope this helps!

Quite a comprehensive answer! Citing sources would make it even better.

Hi @randomhead! Tracking presidential planes is a professional hobby of mine. There is no news about this so I don't have a source... This is all done from my own observations on the matter. You can look over them yourself through the official press digests or flight history! Thanks for commenting though!


text:
Is there a list of aircraft types to be used with a callsign?
In the U.S., general aviation aircraft use the airplane type with the callsign when talking to ATC, such as "Skyhawk 123CS" or "Citation 321CT". ATC likes to know what type of airplane you're flying so they know how what its performance is.
It gets complicated with airplanes like the Cessna Corvalis, which is a Cessna (formerly Columbia) but it is faster than a Cirrus and can fly an approach at 200 kts if required. So what would the callsign of a Corvalis be? "Corvalis 123TT" or "Columbia 123TT"? I doubt it would be "Cessna 123TT".
Is there an official (or unofficial) list of airplane types to use when talking to controllers?

FWIW, it's not only for ATC, it's useful information for other pilots on frequency too. In a C182 I once landed at an uncontrolled airport behind a Citabria, announcing myself as "Cessna". I met the Citabria pilot in the FBO and he said "I thought you said twin Cessna, that's why I kept my pattern so tight". Since then I've said "Skylane" :-)

@Pondlife -- no kidding: imagine being in a Citation and going "Cessna Two Echo Bravo" only to find out everyone was thinking you were a C172, not a jet!

I couldn't find any specific guidance on this, the AIM 4-2-4(a)(3) just says (emphasis mine):

Civil aircraft pilots should state the aircraft
  type, model or manufacturer’s name, followed by the
  digits/letters of the registration number. When the
  aircraft manufacturer’s name or model is stated, the
  prefix “N” is dropped; e.g., Aztec Two Four Six Four
  Alpha.

See also the ATC orders 2-4-21 for the controllers' side. It doesn't give any information either on where to find type and model information and the examples suggest that precision isn't very important:

EXAMPLE−
  “Tri−Pacer.”
  “P A Twenty−Two.”
  “Cessna Four−Oh−One.”
  “Blue and white King Air.”
  “Airliner.”
  “Sikorsky S−Seventy−Six.”

If "airliner" is an acceptable identifier then anything is :-)
As you said, you can comply with the AIM simply by saying "Cessna", whether you're in a 120 or a 750. But what about experimental aircraft, or a type that the controller just doesn't know?
Personally, I think this is a practical issue rather than a formal one. If it was critical for ATC to know the performance of every aircraft then flight plans would be mandatory. As it is, both controllers and pilots rely on their working knowledge of aircraft types and the system just works. The big, fast aircraft are mostly IFR anyway so the controllers already know what to expect; the small, slow ones can all do 80-100 knots in the pattern and the controllers don't need to worry about them much.
In the unusual cases where a specific aircraft type's performance might be an issue, the pilot can always work it out with the controllers:

N12345, Louisville Approach, I need your best forward speed on the approach, can you give me 120 knots?1
Bowman Tower, N12345, we're a warbird, I need a minimum 90 knots in the pattern and request an overhead break for runway 242

1Real example, and no I couldn't
2Also a real example, but sadly not me flying

I wonder if the author's use of "Airliner" in the AIM was meant to refer to the Beech 99 Airliner, or some generic transport category aircraft (presumably jet powered) operated by an air carrier in scheduled service?

They can be found in FAA Order JO 7360.1C - Aircraft Type Designators

Nope. Those are written designators for filing flight plans. This question is about spoken identifiers on the radio.

@Ralph, that document lists the correct manufacturer and model for each type code (and then later lists all models/types for each manufacturer and all manufacturers/types for each model). That seems to me to be the definitive answer to the question "What should I call myself if I'm flying this type?"